WO 2006/095121 discloses apparatus and methods for storing sensitive materials in rigid sealable enclosures. After the sensitive materials, for example molecule compounds dissolved in DMSO, are placed in the enclosure, it is sealed and then purged using a purge gas and preferably left with the interior filled with inert gas at a pressure slightly above ambient so that if there is any problem with the sealing, the leakage occurs from the inside of the container to the outside rather than the other way round, which could lead to contamination and deterioration of the contents stored in the container.
The published specification discloses containers adapted for use in the method as well as a control unit which enables them to be purged and left under excess pressure.
The control unit described is adapted to detect the nature of the gas flow emerging from an exhaust port of the container, and to stop the purging process when the purging has reached an adequate level, for example by detecting that the oxygen level in the gas flow from the container has dropped below a preset concentration. Moisture level in the exhaust gas may also be monitored.
WO 2008/125859 discloses sealable rigid enclosures suitable for use with the apparatus disclosed in WO 2006/095121.
Other such apparatus has been described, for example in U.S. Pat. No. 4,344,467, and (in connection with inerting packaging covers) in U.S. Pat. No. 5,794,408. GB-A-1587534 discloses apparatus for providing a controlled atmosphere around perishable products such as fruit or vegetables located in a flexible bag.